Complex Relation Between Body mass index and endometriosis

The reason of common link between BMI and endometriosis remains unknown.

Key Points

Highlights:

• No relationship was observed between BMI and surgical classification and location of endometriosis.

Importance:

• It is unlikely that BMI plays a central role in the distribution and phenotypic characteristics of endometriosis.

What's done here:

• This observational retrospective cohort study included 471 histologically confirmed endometriosis patients from Australia.
• The aim is to assess the relationship between BMI and the phenotype of endometriotic lesions, as per revised American Society for Reproductive Medicine (rASRM) criteria.
• Lesion type (superficial/deep, peritoneal, ovarian, adhesions) and specific anatomical locations (pelvic sidewall, uterosacral, Douglas, ovarian, utero-vesical, bladder, and pararectal) evaluated.

Key Results:

• More than half of the patients had a normal BMI value, and almost half of the study group was diagnosed with stage 1 endometriosis.
• No association was found between BMI and the presence of deep, superficial, ovarian, or peritoneal endometriosis lesions in this cohort.
• When specific tissues and anatomical locations of endometriosis lesions were compared to BMI, after multiple testing corrections, the probable link was invalidated.

Strength and Limitations:

• The inclusion of only histologically confirmed endometriosis, and the comprehensive statistical analysis, especially strict significance criteria due to correction for multiple testing are strengths.
• A probable selection bias due to the recruitment through an Endometriosis and Pelvic Pain Clinic, hence the absence of a symptom-free population; and a single BMI measurement are limitations.

Lay Summary

This research aimed to find the relationship between BMI and endometriosis especially related to surgical phenotype and lesion location. An observational cohort study was led by  Holdsworth-Carson et al, from Australia. The article was recently published in "RBMO" .

Many earlier studies report that higher BMI is often protective, while lower body mass index (BMI) is associated with endometriosis. 

Four hundred and seventy-one laparoscopically operated and histologically confirmed endometriosis patients from Endometriosis and Pelvic Pain Clinic of the Royal Women's Hospital listed their demographic, symptomatic, and relevant medical information through a survey. The phenotype of endometriotic lesions, such as superficial ovarian, deep ovarian, superficial peritoneal, deep peritoneal, and adhesions, was determined by the laparoscopic surgeon in accordance with the rASRM were compared. Also, the location of the lesions from the pathology reports grouped as the anterior compartment (including ureterovesical fold and bladder), posterior compartment (including uterosacral ligament, Pouch of Douglas, pelvis side wall, ovarian and pararectal endometriosis were evaluated. Statistically, using comprehensive statistical analysis and strict significance criteria by correction for multiple testing, the analysis revealed no association between the localization of endometriosis lesions and BMI in this cohort. 

Apparently, the relationship underlying the interaction between BMI and endometriosis should be extremely complex. It is unlikely that BMI has a wide impact on the mechanisms that affect endometriosis lesion distribution sites or lesion phenotype. 

"This analysis does not conclusively support an influence of BMI on endometriotic lesion phenotype based on surgical classification or location. Further investigation of the physiological disturbances underlying BMI and the promotion of endometriotic lesion phenotypes and their location is warranted, but any effect is likely to be small." concluded the authors.

Research Source: https://pubmed.ncbi.nlm.nih.gov/34511393/